Flameheart Sr's Ashen Lords
Flameheart Senior created four Ashen Lords, each one of them given a different role within his armada and his plans. These were his most elite commanders and stalwart followers who willingly underwent the transformation. The ritual for creating an Ashen Lord involves a Chest of Rage, Ashen Jewels, an Ashen Curse, and a sacrifice.
Old Horatio was the shipwright of Flameheart's fleets and the recruiter, pressganging skellies into servitude aboard his ships. He knew binding magic. His final act was parting the Devil's Shroud with his power before turning to dust.
Red Ruth was the alchemist and weaponsmith, original creator of the Cursed Cannonballs. Either it was the cannons of the Burning Blade themselves or the cannonballs that Red Ruth imbued with curse magic.
Captain Grimm built the fortresses around the Sea of Thieves as places to store and protect treasure that was stolen and meant as tribute for Flameheart Sr.
Warden Chi was in charge of a prison where Flameheart Sr sent enemies who were captured. She was to make sure those kept in incarceration were kept alive, albeit tortured.
A core part of what powers an Ashen Lord is a relic known as an Ashen Jewel, used in conjunction with the Ashen Curse.